On Thursday, May 08, 2014 09:49:36 AM Ulf Hansson wrote: > On 8 May 2014 01:29, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to > > resume all runtime-suspended devices during system suspend, mostly > > because those devices may need to be reprogrammed due to different > > wakeup settings for system sleep and for runtime PM. > > > > For some devices, though, it's OK to remain in runtime suspend > > throughout a complete system suspend/resume cycle (if the device was in > > runtime suspend at the start of the cycle). We would like to do this > > whenever possible, to avoid the overhead of extra power-up and power-down > > events. > > > > However, problems may arise because the device's descendants may require > > it to be at full power at various points during the cycle. Therefore the > > most straightforward way to do this safely is if the device and all its > > descendants can remain runtime suspended until the resume stage of system > > resume. > > > > To this end, introduce dev->power.leave_runtime_suspended. > > If a subsystem or driver sets this flag during the ->prepare() callback, > > and if the flag is set in all of the device's descendants, and if the > > device is still in runtime suspend at the beginning of the ->suspend() > > callback, that callback is allowed to return 0 without clearing > > power.leave_runtime_suspended and without changing the state of the > > device, unless the current state of the device is not appropriate for > > the upcoming system sleep state (for example, the device is supposed to > > wake up the system from that state and its current wakeup settings are > > not suitable for that). Then, the PM core will not invoke the device's > > ->suspend_late(), ->suspend_irq(), ->resume_irq(), ->resume_early(), or > > ->resume() callbacks. Instead, it will invoke ->runtime_resume() during > > the device resume stage of system resume. > > > > By leaving this flag set after ->suspend(), a driver or subsystem tells > > the PM core that the device is runtime suspended, it is in a suitable > > state for system suspend (for example, the wakeup setting does not > > need to be changed), and it does not need to return to full > > power until the resume stage. > > > > Changelog based on an Alan Stern's description of the idea > > (http://marc.info/?l=linux-pm&m=139940466625569&w=2). > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > --- > > drivers/base/power/main.c | 31 ++++++++++++++++++++++++------- > > drivers/base/power/runtime.c | 10 ++++++++++ > > include/linux/pm.h | 3 +++ > > include/linux/pm_runtime.h | 16 ++++++++++++++++ > > kernel/power/Kconfig | 4 ++++ > > 5 files changed, 57 insertions(+), 7 deletions(-) > > > > Index: linux-pm/kernel/power/Kconfig > > =================================================================== > > --- linux-pm.orig/kernel/power/Kconfig > > +++ linux-pm/kernel/power/Kconfig > > @@ -147,6 +147,10 @@ config PM > > def_bool y > > depends on PM_SLEEP || PM_RUNTIME > > > > +config PM_BOTH > > + def_bool y > > + depends on PM_SLEEP && PM_RUNTIME > > + > > Should we not depend on PM_RUNTIME only? Thus we don't need the new > Kconfig, Well, OK. I guess we can tolerate one useless statement in rpm_resume() in case CONFIG_PM_SLEEP is unset. > and then we could rename the new APIs to pm_runtime_* instead. That would just make the name longer - for what value? > > config PM_DEBUG > > bool "Power Management Debug Support" > > depends on PM > > Index: linux-pm/include/linux/pm.h > > =================================================================== > > --- linux-pm.orig/include/linux/pm.h > > +++ linux-pm/include/linux/pm.h > > @@ -583,6 +583,9 @@ struct dev_pm_info { > > unsigned long suspended_jiffies; > > unsigned long accounting_timestamp; > > #endif > > +#ifdef CONFIG_PM_BOTH > > + bool leave_runtime_suspended:1; > > +#endif > > struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */ > > void (*set_latency_tolerance)(struct device *, s32); > > struct dev_pm_qos *qos; > > Index: linux-pm/include/linux/pm_runtime.h > > =================================================================== > > --- linux-pm.orig/include/linux/pm_runtime.h > > +++ linux-pm/include/linux/pm_runtime.h > > @@ -264,4 +264,20 @@ static inline void pm_runtime_dont_use_a > > __pm_runtime_use_autosuspend(dev, false); > > } > > > > +#ifdef CONFIG_PM_BOTH > > +static inline void __set_leave_runtime_suspended(struct device *dev, bool val) > > +{ > > + dev->power.leave_runtime_suspended = val; > > +} > > +extern void pm_set_leave_runtime_suspended(struct device *dev, bool val); > > +static inline bool pm_leave_runtime_suspended(struct device *dev) > > +{ > > + return dev->power.leave_runtime_suspended; > > +} > > +#else > > +static inline void __set_leave_runtime_suspended(struct device *dev, bool val) {} > > +static inline void pm_set_leave_runtime_suspended(struct device *dev, bool val) {} > > +static inline bool pm_leave_runtime_suspended(struct device *dev) { return false; } > > +#endif > > + > > #endif > > Index: linux-pm/drivers/base/power/runtime.c > > =================================================================== > > --- linux-pm.orig/drivers/base/power/runtime.c > > +++ linux-pm/drivers/base/power/runtime.c > > @@ -732,6 +732,7 @@ static int rpm_resume(struct device *dev > > } > > skip_parent: > > > > + __set_leave_runtime_suspended(dev, false); (*) > > if (dev->power.no_callbacks) > > goto no_callback; /* Assume success. */ > > > > @@ -1485,3 +1486,12 @@ out: > > return ret; > > } > > EXPORT_SYMBOL_GPL(pm_runtime_force_resume); > > + > > +#ifdef CONFIG_PM_BOTH > > +void pm_set_leave_runtime_suspended(struct device *dev, bool val) > > +{ > > + spin_lock_irq(&dev->power.lock); > > + __set_leave_runtime_suspended(dev, val); > > + spin_unlock_irq(&dev->power.lock); > > +} > > +#endif > > Index: linux-pm/drivers/base/power/main.c > > =================================================================== > > --- linux-pm.orig/drivers/base/power/main.c > > +++ linux-pm/drivers/base/power/main.c > > @@ -479,7 +479,7 @@ static int device_resume_noirq(struct de > > TRACE_DEVICE(dev); > > TRACE_RESUME(0); > > > > - if (dev->power.syscore) > > + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) > > goto Out; > > > > if (!dev->power.is_noirq_suspended) > > @@ -605,7 +605,7 @@ static int device_resume_early(struct de > > TRACE_DEVICE(dev); > > TRACE_RESUME(0); > > > > - if (dev->power.syscore) > > + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) > > goto Out; > > > > if (!dev->power.is_late_suspended) > > @@ -735,6 +735,11 @@ static int device_resume(struct device * > > if (dev->power.syscore) > > goto Complete; > > > > + if (pm_leave_runtime_suspended(dev)) { > > + pm_runtime_resume(dev); > > + goto Complete; > > + } > > + > > dpm_wait(dev->parent, async); > > dpm_watchdog_set(&wd, dev); > > device_lock(dev); > > @@ -1007,7 +1012,7 @@ static int __device_suspend_noirq(struct > > goto Complete; > > } > > > > - if (dev->power.syscore) > > + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) > > goto Complete; > > > > dpm_wait_for_children(dev, async); > > @@ -1146,7 +1151,7 @@ static int __device_suspend_late(struct > > goto Complete; > > } > > > > - if (dev->power.syscore) > > + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) > > goto Complete; > > > > dpm_wait_for_children(dev, async); > > @@ -1382,10 +1387,21 @@ static int __device_suspend(struct devic > > > > End: > > if (!error) { > > + struct device *parent = dev->parent; > > + > > dev->power.is_suspended = true; > > - if (dev->power.wakeup_path > > - && dev->parent && !dev->parent->power.ignore_children) > > - dev->parent->power.wakeup_path = true; > > + if (parent) { > > + spin_lock_irq(&parent->power.lock); > > + > > + if (dev->power.wakeup_path > > + && !parent->power.ignore_children) > > + parent->power.wakeup_path = true; > > + > > + if (!pm_leave_runtime_suspended(dev)) > > I suppose this is the reason to why you think you need CONFIG_PM_BOTH? Actually, no. The reason is the (*) change in rpm_resume(). > But won't this would work nicely even if we just had CONFIG_PM_RUNTIME? Yes, it will. > > + __set_leave_runtime_suspended(parent, false); > > + > > + spin_unlock_irq(&parent->power.lock); > > + } > > } > > > > device_unlock(dev); > > @@ -1553,6 +1569,7 @@ int dpm_prepare(pm_message_t state) > > struct device *dev = to_device(dpm_list.next); > > > > get_device(dev); > > + pm_set_leave_runtime_suspended(dev, false); > > Is this needed? Yes, it is. We don't want any leftovers after this point. > > mutex_unlock(&dpm_list_mtx); > > > > error = device_prepare(dev, state); > > > > -- Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
